1. CoffeeScript: JavaScript onSteroids
By Jordan Dichev

2. CoffeeScriptis
• “A littlelanguangethat compiles into
JavaScript”
• Easiertoreadandwritethan JavaScript
• SyntacticallyclosetoRubyand Python
• Easytointegratewithexistingcode
• Just JavaScript afterall

3. Main Features
• Significant whitespace and highly expressive
• Bound functional literal and class sugar for prototypes
• Loop, comprehensions and both
• An existential operator
• Splats (variadic parameters)
• Default Parameters
• Heredocs, heregexes
• Automatic lexical scoping

4. Functions
square = (x) ->x * x
(input arguments) -> output definition
var square = function(x) {
return x * x;
}

5. Literals
guys = ['barry', 'larry', 'harry']
console.log guys[0]
elements =
hydrogen = 1
silicon = 14
uranium = 92
console.logelements.silicon

6. Literals
var elements, guys;
guys = ['barry', 'larry', 'harry'];
console.log(guys[0]);
elements = {
hydrogen: 1,
silicon: 14,
uranium: 92
};
console.log(elements.silicon);

7. Whitespace
today = 'tuesday'
if today is 'tuesday'
console.log 'UXEG'
else
console.log 'noop'

8. Whitespace
var today;
today = 'tuesday';
if (today === 'tuesday') {
console.log('UXEG');
} else {
console.log('noop');
}

9. Loops and comprehensions
list = ['a', 'b', 'c']
console.log letter for letter in list
process =
good: 'good'
bad: 'bad'
console.log name for name of process
console.logi for i in [0..10]

10. List comprehensions
vari, letter, list, name, process, _i, _j, _len;
list = ['a', 'b', 'c'];
for (_i = 0, _len = list.length; _i< _len; _i++) {
letter = list[_i];
console.log(letter);
}
process = { good: 'good', bad: 'bad’ };
for (name in process) {
console.log(name);
}
for (i = _j = 0; _j<= 10; i = ++_j) {
console.log(i);
}

11. Existential operator
person =
name: 'John Doe'
age: 28
console.logperson.name.length
console.logperson.non?.existent.property
console.logperson.name.reverse?()

12. Existential operator
varperson, _base, _ref;
person = {
name: 'John Doe',
age: 28
};
console.log(person.name.length);
console.log((_ref = person.non) != null ? _ref.existent.property :
void 0);
console.log(typeof (_base = person.name).reverse === "function"
? _base.reverse() : void 0);

13. Classes
class Message
show: ->
console.log 'Foo'
class BarMessage extends Message
show: ->
console.log 'Bar’
new BarMessage().show()

14. Conditionals
if a
console.log "a is true"
else
console.log "a is false”
console.log "a is false" unless a

15. Scope
a = 'A'
myFunc = ->
a = 'AAA'
b = 'B'

16. Scope
(function() {
var a, myFunc;
a = 'A’;
myFunc = function() {
varb;
a = 'AAA';
return b = 'B';
};
}).call(this);

17. String Interpolation
name = "John Doe"
console.log "Hello #{name}"
console.log 'Hello #{name}'

18. String Interpolation
var name;
name = "John Doe";
console.log("Hello " + name);
console.log('Hello #{name}');

19. Building
coffee – a command line tool
cake – a simple build tool
coffee -w -o lib/ -jmergedSource.js-csrc/
-w – to watch for changes while we write
-o – to specify output location
-j – to merge all files into one
-c – to specify input location